Accelerating gas system for gas-operated firearms

ABSTRACT

The invention pertains to a gas system for firearms which has a delayed accelerating feature controlling the action bar assembly. In gas operated extraction-ejection systems, considerable stress and shock is normally transmitted to the action bar assembly and its associated extraction-ejection apparatus. The stress is reduced in the present system by providing a gradual acceleration to the action bar assembly. The accelerating effect is accomplished by means of a novel piston-cylinder arrangement that provides an increase in velocity towards the end of the functioning cycle.

Unite States Patent Alday 4 1 Dec. 26, 1972 [54] ACCELERATING GAS SYSTEM FOR GAS-OPERATED FIREARMS [72] Inventor: James M. Alday, Williamson, N.Y.

[73] Assignee: Remington Arms Company, Inc., Bridgeport, Conn.

[22] Filed: March 10, 1970 [21] Appl. No.: 18,159

52 US. Cl .39/193 51 Int. Cl ..F4ld 5/08 58 Field of Search ..89/l9l, 192, 193

[56] References Cited UNITED STATES PATENTS 960,825 6/1910 Colleoni ..89/l93 UX 3,246,567 4/1966 Miller 2,582,989 1/1952 Harvey ..89ll93 FOREIGN PATENTS 0R APPLICATIONS 408,304 l2/l944 ltaly ..89/l9l Primary Examiner-Benjamin A. Borchelt Assistant ExaminerStephen C. Bentley Attorney-John H. Lewis, Jr. and Nicholas Skovran [57] ABSTRACT The invention pertains to a gas system for firearms which has a delayed accelerating feature controlling V the action bar assembly. In gas operated extractionejection systems, considerable stress and shock" is normally transmitted to the action bar assembly and its associated extraction-ejection apparatus. The stress is reduced in the present system by providing a gradual acceleration to the action bar assembly. The accelerating effect is accomplished by means of a novel piston-cylinder arrangement that provides an increase in velocity towards the end of the functioning cycle.

3 Claims, 3 Drawing Figures PATENTEDDEBZB I912 3.707.110

/ 5 [fryer/tor dames M A/og-y ACCELERATING GAS SYSTEM FOR GAS- OPERATED FIREARMS The present invention relates to gas-operated firearms, and more particularly to a gas system having an improved piston and cylinder arrangement for imparting movement to an action bar assembly.

One of the problems usually concomitant with the use of high energy ammunition in automatic weaponry is the increase in the stresses and shock upon the extractor-ejector parts. Various gas systems have been devised to counteract the initial high surges of gas energy by providing a cushioning effect to the piston. Such systems are generally shown by patents to:

J. M. MILLER, US. Pat. No. 2,800,059, issued July 23, 1957; and

A. J. LIZZA, US. Pat. No. 3,166,983, issued Jan. 26, 1965.

The Miller device produces a slow initial movement of the piston by causing the actuating gas to flow through a venturi aperture. This delays the motion of the piston until after an initial high pressure build-up is encountered.

In the Lizza device, gases from the barrel of the gun are first admitted ahead of the piston to cushion the gas forces which subsequently act to drive the piston.

Still other systems have vented the high-pressure gas until a safer operating pressure level was reached.

In all of the above, attempts to decrease the working stresses have been accomplished by manipulating or varying the gas.

The present device, although having the same objective of reducing the stress and shock upon the extractor-ejector mechanism, does not modify the gas acting upon the piston. Rather, the present system provides for full introduction of the gases to the cylinder, but varies the effects by changing the piston surface over which the gases are allowed to act.

Although the effect is basically the same, the means of accomplishing the effect is different, and has certain distinct advantages over the prior art.

In the first instance, the invention is simpler in its construction and operation.

Secondly, the present device can still function with ammunition of lower energy, which is not necessarily the case in the other systems.

Thirdly, the present system has a more pleasing appearance.

Reference is also made to the systems of W. C. Roemer and E. M. Harvey, U.S. Pats. Nos. 2,372,339, issued Mar. 27, 1945; and 2,582,989, issued Jan. 22, 1952, respectively.

In these devices the gases are forced to act over different areas of the piston surface, not unlike the present system. But unlike the present device, the gases act only momentarily on the reduced area. Once the piston starts to move, the gases act over the entire piston surface.

The present invention has a piston with an interior cavity upon which the gas is allowed to act. The gases continue to act over the smaller diametral surface area of the piston cavity even though the piston starts to move. It is only after the piston has moved a defined distance that the gases will act upon the greater piston area. This method has the advantage of providing a more uniform energy transition to the piston and working parts by providing a smoother accelerating effect.

Extraction and ejection is accomplished by imparting movement to an inertia weight and its attached action bars. The inertia weight and action bar assembly are made to accelerate along with the piston of the gas system almost from the initial movement of the piston. The speed-up in acceleration of the piston towards the end of the cycle imparts the added energy to the action assembly and the bolt carrier of the extraction-ejection mechanism to complete the cycle.

It is an object of the present invention to provide an automatic gas-operated firearm which will fire high energy ammunition without creating undesirable stresses and shock in the extraction-ejection mechanism.

It is another object ofthe invention to provide an'automatic gas-operated firearm with a gas system which will increase the velocity of the action bar assembly towards the end of the functioning cycle.

It is a further object of the invention to provide a gas system for an automatic gas-operated firearm which contains a piston-cylinder arrangement, wherein the piston contains a cavity having an interior surface upon which the gases impinge.

It is contemplated by this invention to provide a gas system for a gas-operated firearm which will impart a smooth accelerating force to the action bar assembly.

Other objects and advantages will become apparent with reference to the subsequent detailed description and the accompanying drawings, which for the purposes of invention, are merely exemplary hereto, said drawings in which:

FIG. 1 shows the gas system in its initial at-rest state before firing;

FIG. 2 depicts the gas system after firing and just prior to when the piston accelerates due to the gases acting upon the enlarged piston area; and

FIG. 3 illustrates the gas system at the end of its cycle after the gases have acted upon the enlarged piston area.

Generally speaking, the invention is for a gas system for firearms wherein a piston is slidably disposed within a cylinder. Gases produced from ammunition combustion are conveyed from the barrel to the cylinder, where they impinge upon a portion of the pistons diametral surface area. The gases continue to impinge upon this limited portion of the piston even after the piston has started to move within the cylinder. Part way through the stroke, the gases are allowed to act upon the entire diametral surface area of the piston causing it to accelerate in the final stroke period.

By providing the impingement of the gases over only a portion of the pistonss diametral surface area when the piston is at rest and for a limited time thereafter, a smooth initial accelerating effect is produced.

The above effect is produced by providing the piston with an elongated cavity which receives the gases when the piston is in a rest position. A plug fixedly attached to the cylinder having an elongated protuberance extending into the hollow of the cylinder is received in the cavity of the piston to form an expandable chamber.

When the gases are admitted to the chamber, the rear wall of the elongated cavity acts as part of the diametral surface area of the piston, causing the piston to move under the action of the gas. The piston will move away from its rest position until a point is reached whereby the protuberance clears the cavity wall of said piston, thus allowing the gases to act upon the entire diametral surface area of the piston causing it to accelerate.

Now referring to FIG. 1, the gas system of the invention is shown in its initial at-rest state before firing. A piston 3 is slidably disposed within a hollow cylinder 4. Gas is admitted from barrel 1 into the cylinder through port 9 and empties into a hollow slot 19 formed in the outer piston wall. The gas is next conveyed into the interior of the piston through hole 7.

A plug 8 is fixed to the end of the cylinder 4, and has a protuberance 18. The protuberance fits into an elongated cavity of the piston whose walls are defined by surfaces 6 and 6' (see FIG. 2). a

In the at-rest condition, the plug fills most of the interior of the cavity, leaving a small space between the end of the protuberance 18, and the back wall 6'of the cavity.

The gases act upon the back wall 6 of the piston cavity and cause it to move away from the plug 8 (see FIG. 2).

When the piston clears the end of the protuberance 18 as shown in FIG. 2, the gases will escape into the hollow of the cylinder 29, which is formed in the cylinder when the piston slides away from the plug. The gases will now act upon the entire diametral area of the piston as depicted by surfaces 6, 6", and 6", as shown in FIG. 3.

The surface shown as 6 is a lateral interior surface of the piston, and while receiving the impingement of the gas, does not contribute an actionable surface by which the gases force the piston to move in the cylinder.

The surface 6" is a chamfered surface in the end face of the piston. The chamfer helps to seat the piston upon protuberance 18. As far as surface 6" presents a partial transverse surface area to the gases, it contributes movement to the piston.

In the at-rest position (FIG. 1), and until the time the piston moves completely away from the plug (FIG. 2), the gases act upon surface 6 of the piston cavity. This smaller surface area provides a lesser gas force. to the piston, than that presented when the gases can act over surfaces 6, 6", and 6'.

It should be noted that the interior wall 6 of the cavity adds to the entire actionable surface when the gases flow into cavity 29, since this surface makes up a portion of the transverse (or normal) surface over which the gas will act to move the piston.

Thus, for the initial portion of the stroke, the cylinder is accelerated slowly, and for the final portion of the stroke the piston has a greater acceleration.

The gases are vented to the atmosphere in the final portions of the piston stroke as can be seen in FIG. 3. This allows the interior of the cylinder to stay clean, since the exhausting gases purge the mechanism of soot and other foul remnants of combustion.

The exhausting of the gases takes place when the end portion 17 of the elongated hollow slot 19 of the piston clears the end face 12 of the cylinder. At this time, the pent-up gases are free to escape from the hollow recesses of the cylinder and piston.

The gases may be vented in a downward direction if so desired, by placing a venting slot 19 below the piston, rather than above it as shown. This slot would necessarily have to be in communication with cavity 29 and/or the cavity of the piston.

FIG. 3 illustrates the gas system at the end of its travel after the gases have acted upon the enlarged piston area. The piston is prevented from further movement by the spring guide 5 which rests within cavity 14 of the piston (FIG. 1). The piston is forced to slide upon the spring guide as it accelerates, and the guide acts as a stop for the piston at the end of its stroke (FIG. 3). The piston is brought to rest when the tip 16 of the guide comes in contact with the end of the piston aperture 15.

There is a small clearance y (FIG. 1) which represents a 0.050 inch separation between the piston 3 and the inertia weight 25. Just after the piston begins its travel, it contacts the inertia weight and forces it to move with it. The inertia weight 25 has action bars attached thereto (not shown). As the inertia weight is forced to move, the action bars also force the carrier and bolt assembly (not shown) to move and provide extraction and ejection. The exact nature of the carrier, 7

bolt, and other associated parts is irrelevant, since any standard parts now used for short stroking gas systems could be adapted to the present apparatus.

The action spring 23 is compressed upon the spring guide 5, when the piston moves rearward. A force is produced by this compression which serves to close the action and chamber a fresh round upon completion of the rearward stroke of the action bar assembly.

The spring guide 5 is fixedly positioned against the receiver and serves as a guide for the compressing function of the spring, as well as a piston stop.

In addition, the inertia weight is guided and supported by this element.

The present gas system not only presents a novel accelerating system characterized by a piston having an interior elongated cavity, but the means of introducing the gases to this cavity is unique in that it also serves the purpose of acting as the means, by which the gases are vented to the atmosphere. I I

The most unusual aspect of the above arrangement probably is the elongated slot. The slot stays in communication with port 9 to receive the gases during the entire travel of the piston. This same slot vents the gases when the edge of the slot clears the end of the cylinder at the end of the piston stroke.

Many modifications of this invention will be apparent to the skilled practitioner, for example: the amount of action (acceleration effect) is dependent upon the relative areas of the cavity and gas cylinder. As such, varying the dimensions of the piston and plug parts can provide for a quicker or slower response.

It is also possible to have the piston-plug arrangement inverted, wherein the piston has a two-step configuration. The first step comprises a portion of the pistons diametral surface area for receiving the impingement of the gases when the piston is at rest and for a portion of the stroke thereafter, and the second step comprises the remainder of the diametral surface area of the piston for receiving the impingement of the gases when the piston is in the remaining portion of the stroke cycle. The plug element has a cavity to house the first step of the piston when the piston is in its rest position. A small space is formed in the plug cavity between the plug and the piston for receiving the combustion gases, thus presenting an expandable gas chamber within the plug as the piston moves from its rest position away from said plug. When the first step of the piston slides out of the cavity, the gases will act over the entire piston surface area.

Many such modifications and variations as exemplified above will naturally occur to those skilled in the art, and are considered to be within the purview of the spirit and scope of the invention as depicted by the appended claims.

What is claimed is:

l. A gas-operated firearm having a barrel; a gas system comprising a substantially hollow cylinder connected to the barrel and communicating therewith to receive the combustion gases of ammunition; said system further comprising:

a plug fixedly attached to the cylinder having an elongated protuberance extending into the hollow portion thereof;

a piston slidably disposed within said cylinder having a diametral surface upon which the combustion gases impinge; said surface including a rear wall of an elongated cavity; said cavity opening unto the surface for receiving said protuberance when the piston is in a rest position; a small space being formed between the protuberance and the rear wall of the cavity to present an expandable chamber within said piston as the piston slides from its rest position; and

means within said cylinder to conduct the combustion gases to said chamber characterized by a port extending from the barrel into the cylinder; said port opening unto an elongated hollow slot formed in an outer wall of the piston; and a hole extending from the slot to the interior chamber of said piston, whereby the gases impinge upon the rear wall of the cavity causing the piston to move from its rest position, under the force of said gases,

away from said plug until a point is reached whereby the protuberance clears the cavity opening of said piston, allowing the gases to substantially act upon the entire diametral surface of the piston causing said piston to accelerate.

2. The gas-conducting means of claim 1, further characterized in that said means serves the additional purpose of venting the gases to the atmosphere when the piston is substantially at the end of its stroke; said venting taking place as the piston slides within the cylinder to a position wherein the slot of the piston extends past an edge of the cylinder, exposing the cylinder and the interior cavity of said piston to the atmosphere.

3. In a gas-operated firearm, an improved gas-operating system comprising:

a gas cylinder having a closed end;

a gas admission port in the wall of said cylinder;

an elongated protuberance extending into said cylinder from the closed end thereof;

a piston slidably reciprocable in said cylinder for a distance greater than the length of said protuberance; said piston having an interior cavity extending to its diametral surface wherein the cavity is engageable with said protuberance when the piston is in the end of the cylinder adjacent the closed end; and a gas conduit in said piston communicating between said gas port and the innermost end of said cavity, whereby gas entering said cylinder through said gas port can be admitted to the innermost end of said cavity to interact between said protuberance and the innermost end of said cavity and after said piston has been moved thereby for a distance equal to the length of said protuberance can pass through said cavity to the closed end of the cylinder to interact between the closed end and the diametral surface of the piston.

lO6Ol2 0066 

1. A gas-operated firearm having a barrel; a gas system comprising a substantially hollow cylinder connected to the barrel and communicating therewith to receive the combustion gases of ammunition; said system further comprising: a plug fixedly attached to the cylinder having an elongated protuberance extending into the hollow portion thereof; a piston slidably disposed within said cylinder having a diametral surface upon which the combustion gases impinge; said surface including a rear wall of an elongated cavity; said cavity opening unto the surface for receiving said protuberance when the piston is in a rest position; a small space being formed between the protuberance and the rear wall of the cavity to present an expandable chamber within said piston as the piston slides from its rest position; and means within said cylinder to conduct the combustion gases to said chamber characterized by a port extending from the barrel into the cylinder; said port opening unto an elongated hollow slot formed in an outer wall of the piston; and a hole extending from the slot to the interior chamber of said piston, whereby the gAses impinge upon the rear wall of the cavity causing the piston to move from its rest position, under the force of said gases, away from said plug until a point is reached whereby the protuberance clears the cavity opening of said piston, allowing the gases to substantially act upon the entire diametral surface of the piston causing said piston to accelerate.
 2. The gas-conducting means of claim 1, further characterized in that said means serves the additional purpose of venting the gases to the atmosphere when the piston is substantially at the end of its stroke; said venting taking place as the piston slides within the cylinder to a position wherein the slot of the piston extends past an edge of the cylinder, exposing the cylinder and the interior cavity of said piston to the atmosphere.
 3. In a gas-operated firearm, an improved gas-operating system comprising: a gas cylinder having a closed end; a gas admission port in the wall of said cylinder; an elongated protuberance extending into said cylinder from the closed end thereof; a piston slidably reciprocable in said cylinder for a distance greater than the length of said protuberance; said piston having an interior cavity extending to its diametral surface wherein the cavity is engageable with said protuberance when the piston is in the end of the cylinder adjacent the closed end; and a gas conduit in said piston communicating between said gas port and the innermost end of said cavity, whereby gas entering said cylinder through said gas port can be admitted to the innermost end of said cavity to interact between said protuberance and the innermost end of said cavity and after said piston has been moved thereby for a distance equal to the length of said protuberance can pass through said cavity to the closed end of the cylinder to interact between the closed end and the diametral surface of the piston. 